What does corrosion mean?
Corrosion is the gradual destruction of a material — most often metal — through chemical reaction with substances in its environment, such as oxygen, moisture, acids, or salts. The most familiar example is the rusting of iron and steel, but corrosion affects many materials and structures, from pipelines and ships to bridges and electronics. Engineers speak of corrosion resistance when describing alloys like stainless steel that withstand such attack. Beyond metallurgy, the term is applied figuratively to describe anything being slowly eaten away or weakened, including body tissue damaged by caustic chemicals. The word carries strongly negative connotations: corrosion implies insidious, progressive damage that is easy to overlook until it becomes costly or dangerous. It derives from Latin roots meaning 'to gnaw' or 'to eat away', which captures its essential character — destruction that works bit by bit rather than all at once.
Gradual destruction or impairment of a material, especially metal, by chemical action such as oxidation.
"Salt water accelerated the corrosion of the ship's hull."
In engineering contexts, corrosion is often categorized as uniform, galvanic, pitting, or crevice corrosion.
A condition of gradual wasting away or eating into something, including organic tissue acted upon by corrosive agents.
"The doctor noted corrosion of the tooth enamel from years of acidic drinks."
This extended sense appears mainly in medical and dental contexts.
Corrosion is usually treated as a singular mass noun; a plural form exists but is rare, typically appearing only when referring to multiple distinct instances of corroded damage.
"Inspectors documented several separate corrosions across the pipeline's weld joints."
Corrosion quietly costs the world economy an estimated trillions of dollars each year — more than many nations' entire GDP.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of corrosion
Corrosion comes from the Latin 'corrosio', meaning a gnawing or eating away, itself derived from 'corrodere' ('com-' plus 'rodere', to gnaw) — the same root that gives English 'rodent' and 'erode'. The word entered English in the late medieval or early modern period, with its modern technical sense of chemical attack on metals becoming firmly established during the industrial era as engineers grappled with rust and metal fatigue. Cognates include 'corrosive' and 'corrode', both direct descendants of the same Latin root.
Related word forms
How corrosion is actually used
Corrosion is used chiefly in technical, industrial, and scientific contexts but is well understood in general usage. It carries an inherently negative connotation of decay and hidden damage. In chemistry it specifically denotes electrochemical or chemical attack on materials; in medicine it may describe tissue damage from caustic agents.
Easily confused with corrosion
Erosion is the wearing away of material primarily by physical force (wind, water, abrasion), whereas corrosion is destruction through chemical reaction with the environment.
Corrasion refers to mechanical erosion of rock by material carried in moving water or ice, while corrosion is chemical deterioration.